World’s largest solar thermal plant now fully operational

After three years of construction, the Ivanpah Solar Electric Generating System (ISEGS) is now operational. The 392 MW plant, funded by NRG, Google, and BrightSource Energy, is expected to generate enough electricity to power 140,000 homes, each year. NRG announced last week that each of the plant's three units is now supplying electricity to California's grid.

The Ivanpah plant cost US$2.2 billion to build and stretches over 3,500 acres (more than 1,400 hectares). ISEGS is the largest solar power plant of its kind, accounting for nearly 30 percent of solar power generated in the US. It uses 173,500 heliostats (computer-controlled mirrors) that follow the sun's trajectory and reflect its light towards three solar receiving water boiler towers. The boilers superheat steam to temperatures of up to 550° C (over 1,000° F), which drives standard turbines to generate electricity.

The electricity produced by Units 1 and 3 at Ivanpah, accounting for 259 MW, is being sold to Pacific Gas & Electric under two "long-term power purchase agreements.." The remaining 133 MW generated by Unit 2 is being sold to Southern California Edison with similar terms.

"Cleantech innovations such as Ivanpah are critical to establishing America's leadership in large-scale, clean-energy technology that will keep our economy globally competitive over the next several decades," says NRG Solar's president Tom Doyle. "We see Ivanpah changing the energy landscape by proving that utility-scale solar is not only possible, but incredibly beneficial to both the economy and in how we produce and consume energy."

Ivanpah's construction has not been without controversy. Its huge scale means that a great deal of open land has been used, which had previously been the preserve of the native flora and fauna. Furthermore, there are continued reports of birds being killed by flying into the mirrors or being scorched to death as they fly over the plant.

Eric Davis, assistant regional director for migratory birds at the US Fish and Wildlife Service's Sacramento office has been reported as saying, "We're trying to figure out how big the problem is and what we can do to minimize bird mortalities. When you have new technologies, you don't know what the impacts are going to be."

The California Energy Commission has stated that while Ivanpah will impact the local environment, its benefits outweigh the disadvantages.